WORKERS AHEAD!
You are viewing the development documentation for the Apereo CAS server. The functionality presented here is not officially released yet. This is a work in progress and will be continually updated as development moves forward. You are most encouraged to test the changes presented.
To view the documentation for a specific Apereo CAS server release, please choose an appropriate version. The release schedule is available here.Simple Multifactor Authentication - Communication Strategy
Users may be notified of CAS-issued tokens via text messages and/or email. The authenticated CAS principal is expected to carry enough attributes, configurable via CAS settings, in order for CAS to properly send text messages and/or email to the end-user. Tokens may also be shared via notification strategies back by platforms such as Google Firebase, etc.
To learn more about available options, please see this guide or this guide, or this guide.
The following settings and properties are available from the CAS configuration catalog:
cas.authn.mfa.simple.mail.attribute-name=mail
Principal attribute name that indicates the destination email address for this message. The attribute must already be resolved and available to the CAS principal. |
cas.authn.mfa.simple.mail.from=
Email from address. |
cas.authn.mfa.simple.mail.subject=
Email subject line. This setting supports the Spring Expression Language. |
cas.authn.mfa.simple.sms.attribute-name=phone
Principal attribute name that indicates the destination phone number for this SMS message. The attribute must already be resolved and available to the CAS principal. |
cas.authn.mfa.simple.sms.from=
The from address for the message. |
cas.authn.mfa.simple.sms.text=
The body of the SMS message. |
cas.authn.mfa.simple.mail.bcc=
Email BCC address, if any. |
cas.authn.mfa.simple.mail.cc=
Email CC address, if any. |
cas.authn.mfa.simple.mail.html=false
Indicate whether the message body should be evaluated as HTML text. |
cas.authn.mfa.simple.mail.reply-to=
Email Reply-To address, if any. |
cas.authn.mfa.simple.mail.text=
Email message body. Could be plain text or a reference to an external file that would serve as a template. If specified as a path to an external file with an extension |
cas.authn.mfa.simple.mail.validate-addresses=false
Set whether to validate all addresses which get passed to this helper. |
The following settings may also need to be defined to describe the mail server settings:
spring.mail.default-encoding=UTF-8
Default MimeMessage encoding. |
spring.mail.host=
SMTP server host. For instance, 'smtp.example.com'. |
spring.mail.jndi-name=
Session JNDI name. When set, takes precedence over other Session settings. |
spring.mail.password=
Login password of the SMTP server. |
spring.mail.port=
SMTP server port. |
spring.mail.properties=
Additional JavaMail Session properties. |
spring.mail.protocol=smtp
Protocol used by the SMTP server. |
spring.mail.test-connection=false
Whether to test that the mail server is available on startup. |
spring.mail.username=
Login user of the SMTP server. |
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc. When possible, properties should be stored in
lower-case kebab format, such as cas.property-name=value.S ettings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.
Rate Limiting
CAS is able to support rate-limiting for token requests based on the token-bucket
algorithm, via the Bucket4j project. This means that token requests that reach a certain configurable capacity within
a time window may either be blocked or throttled to slow down. This is done to
protect the system from overloading, allowing you to introduce a scenario to allow CAS 120 token requests per minute with a refill rate of 10 requests per
second that would continually increase in the capacity bucket. Please note that the bucket allocation strategy is specific to the client IP address.
The following settings and properties are available from the CAS configuration catalog:
cas.authn.mfa.simple.bucket4j.bandwidth[0].capacity=120
Number of tokens/requests that can be used within the time window. |
cas.authn.mfa.simple.bucket4j.bandwidth[0].duration=PT60S
Time window in which capacity can be allowed. This settings supports the
|
cas.authn.mfa.simple.bucket4j.bandwidth[0].initial-tokens=
By default initial size of bucket equals to capacity. But sometimes, you may want to have lesser initial size, for example for case of cold start in order to prevent denial of service. |
cas.authn.mfa.simple.bucket4j.bandwidth[0].refill-count=10
The number of tokens that should be used to refill the bucket given the specified refill duration. |
cas.authn.mfa.simple.bucket4j.bandwidth[0].refill-duration=PT30S
Duration to use to refill the bucket. This settings supports the
|
cas.authn.mfa.simple.bucket4j.bandwidth[0].refill-strategy=GREEDY
Describes how the bucket should be refilled. Specifies the speed of tokens regeneration. Available values are as follows:
|
cas.authn.mfa.simple.bucket4j.bandwidth=
Describe the available bandwidth and the overall limitations. Multiple bandwidths allow for different policies per unit of measure. (i.e. allows 1000 tokens per 1 minute, but not often then 50 tokens per 1 second). |
cas.authn.mfa.simple.bucket4j.blocking=true
Whether the request should block until capacity becomes available. Consume a token from the token bucket. If a token is not available this will block until the refill adds one to the bucket. |
cas.authn.mfa.simple.bucket4j.enabled=true
Decide whether bucket4j functionality should be enabled. |
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc. When possible, properties should be stored in
lower-case kebab format, such as cas.property-name=value.S ettings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.
Token Management
Token management and issuance can be handled by CAS directly, or can be outsources to external systems and services.
Default
By default, tokens issued by CAS are tracked using the ticket registry and are assigned a configurable expiration policy controlled via CAS settings. In this option, CAS itself is in charge of managing and validating tokens using pre-configured policies and components.
The following settings and properties are available from the CAS configuration catalog:
cas.authn.mfa.simple.token.core.time-to-kill-in-seconds=30
Time in seconds that CAS tokens should be considered live in CAS server. |
cas.authn.mfa.simple.token.core.token-length=6
The length of the generated token. |
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc. When possible, properties should be stored in
lower-case kebab format, such as cas.property-name=value.S ettings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.
REST
Token validation and management can also be outsources to an external REST API.
The following settings and properties are available from the CAS configuration catalog:
cas.authn.mfa.simple.token.rest.url=
The endpoint URL to contact and retrieve attributes. |
cas.authn.mfa.simple.token.rest.basic-auth-password=
If REST endpoint is protected via basic authentication, specify the password for authentication. |
cas.authn.mfa.simple.token.rest.basic-auth-username=
If REST endpoint is protected via basic authentication, specify the username for authentication. |
cas.authn.mfa.simple.token.rest.headers=
Headers, defined as a Map, to include in the request when making the REST call. Will overwrite any header that CAS is pre-defined to send and include in the request. Key in the map should be the header name and the value in the map should be the header value. |
cas.authn.mfa.simple.token.rest.method=GET
HTTP method to use when contacting the rest endpoint. Examples include |
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc. When possible, properties should be stored in
lower-case kebab format, such as cas.property-name=value.S ettings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.
The API service is primarily response for two operations: issuing tokens so they may be shared with the end-user and validating tokens once the end-user provides them back to CAS.
Generating Tokens
When tokens need to be generated, this API endpoint would be invoked via a GET to create the ticket identifier. The body of
the request will contain the authenticated principal that is put through the multifactor authentication flow,
and the requesting application for which the token should be generated is passed to the API via a service parameter.
The endpoint is expected to respond to token generation requests at a /new URL path suffix, and should produce a 2xx
status code where the response body is expected to contain the token identifier.
Storing Tokens
Generated tokens, that are shared with end-users, can be stored via the REST API endpoint using a POST. The body of the request
would contain the actual token definition and details that should be stored. The API service should produce a 2xx
status code on successful operations.
Validating Tokens
Generated tokens are passed to this API to validation where the token is appended to the URL endpoint and acts as a path variable. The response
that is returned to a GET call must be accompanied by a 2xx status code where the body should contain id and attributes fields, the
latter being optional, which represent the authenticated principal for CAS:
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{
"@class": "org.apereo.cas.authentication.principal.SimplePrincipal",
"id": "casuser",
"attributes": {
"@class": "java.util.LinkedHashMap",
"names": [
"java.util.List", ["cas", "user"]
]
}
}